If 18 of every 33 students attending a school are female, what fraction of the school is female?

The problem statement tells you the fraction is 18/33. In reduced form, this is

... 6/11

a complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x2 = −1. because no real number satisfies this equation, i is called an imaginary number. has no real solution, since the square of a real number cannot be negative.